I just installed plan9 in my PC, where there are many partitions. I can
give you a "fdisk -l /dev/hda":
omitting empty partition (8)

Disk /dev/hda: 40.0 GB, 40020664320 bytes
16 heads, 63 sectors/track, 77545 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/hda1               1         128       64480+  83  Linux
/dev/hda2   *         129       20318    10175760   39  Plan 9
/dev/hda3           20319       20839      262584   82  Linux swap / Solaris
/dev/hda4           20840       77543    28578767+   f  W95 Ext'd (LBA)
/dev/hda5           20840       41157    10240240+  83  Linux
/dev/hda6           41158       52784     5859976+  83  Linux
/dev/hda7           52785       77542    12478000+  83  Linux


I did the Plan9 partition using Linux fdisk. Well... after the plan9 CD
installation (I downloaded the iso a few hours ago), I started linux
again and the SuperBlock of my Reiserfs partition /dev/hda7 had been
overwritten. I had to run reiserfsck --rebuild-sb, and it fixed almost
everything. Further reiser checking fixed something with two tmp files
(the partition is quite full and with many files. Nice only two files
were bad.)

I don't know if I'm the only one having problems with PC partitions (I
guess not), but I'd prefer feeling like Plan9 couldn't have done this
little exter-partition writting.

I hope running Plan9 won't break anything more. hda7 is my linux /home
partition.